Laboratory evaluation of airborne particulate control treatments for simulated aircraft crash recovery operations involving carbon fiber composite materials

2015 ◽  
Vol 13 (5) ◽  
pp. 468 ◽  
Author(s):  
Matthew Ferreri, MS, CIH ◽  
Jeremy Slagley, PhD, CIH, CSP ◽  
Daniel Felker, PhD
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Composite Fiber ◽  
Airborne Particulate ◽  
Treatment Protocols ◽  
Median Diameter ◽  
Particulate Control ◽  
Crash Recovery ◽  
Aircraft Crash

Objective: This study compared four treatment protocols to reduce airborne composite fiber particulates during simulated aircraft crash recovery operations. Design: Four different treatments were applied to determine effectiveness in reducing airborne composite fiber particulates as compared to a “no treatment” protocol. Both “gold standard” gravimetric methods and real-time instruments were used to describe mass per volume concentration, particle size distribution, and surface area. The treatment protocols were applying water, wetted water, wax, or aqueous film-forming foam (AFFF) to both burnt and intact tickets of aircraft composite skin panels. The tickets were then cut using a small high-speed rotary tool to simulate crash recovery operations.Setting: Aerosol test chamber.Subjects, participants: None.Interventions: Airborne particulate control treatments.Main outcome measures: Measures included concentration units of milligrams per cubic meter of air, particle size distribution as described by both count median diameter and mass median diameter and geometric standard deviation of particles in micrometers, and surface area concentration in units of square micrometers per cubic centimeter. Finally, a Monte Carlo simulation was run on the particle size distribution results. Comparison was made via one-way analysis of variance.Results: A significant difference (p < 0.0001) in idealized particle size distribution was found between the water and wetted water treatments as compared to the other treatments for burnt tickets.Conclusions: Emergency crash recovery operations should include a treatment of the debris with water or wetted water. The resulting increase in particle size will make respiratory protection more effective in protecting the response crews.

scholarly journals Conductivity prediction of proppant-packs based on particle size distribution under variable stress conditions

2020 ◽  
Vol 205 ◽  
pp. 03010
Author(s):  
Tiancheng Liang ◽  
Jinwei Zhang ◽  
Chuanyou Meng ◽  
Nailing Xiu ◽  
Bo Cai ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Hydraulic Fracturing ◽  
Size Distribution ◽  
Particle Diameter ◽  
Particle Packing ◽  
Stress Conditions ◽  
Sieve Analysis ◽  
Proper Size ◽  
Median Diameter

The conductivity of the proppant-packs is critical in the productivity of hydraulically fractured wells. Proppants are also the best medium for studying particle packing. Sand and ceramic media are two most common proppants used for hydraulic fracturing. This study focuses on investigate the relation between conductivity and properties of proppant-packs, the particle-size distribution, porosity and mean particle diameter have been measured. The porosity of the proppant pack under zero pressure is determined from bulk density and apparent density. To accurately measure the porosity under variable closed stress conditions, the compressed width was taken into consideration. The particle size distribution was measured from sieve analysis. The paper presents results obtained by conducting routine conductivity test on a variety of proppants. The conductivity-porosity relationships are nonlinear. The conductivity is most sensitive to mean grain size, followed by closed stress, and then sorting. Larger median diameter always correlates to higher conductivity at low stress. Loss of conductivity with stress is more severe for large particles sands than small particles. The binomial method can be used to calculate the conductivity of different types and mesh proppants, which is shown to fit conductivity-mean diameter data successfully. The research is of guiding significance to choose the proper size distribution proppants in hydraulic fracturing. Meanwhile, the binomial method is a better predictor of proppant-packs conductivity based on particle size distribution.

Pulsed Wire Discharge Apparatus for Mass Production of Nanosized Powders

2006 ◽  
Vol 11-12 ◽  
pp. 315-318 ◽  
Author(s):  
Seigo Nishimura ◽  
Y. Hayashi ◽  
Tsuneo Suzuki ◽  
Tadachika Nakayama ◽  
Hisayuki Suematsu ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Mass Production ◽  
Nanosized Powders ◽  
Pulsed Wire Discharge ◽  
Surface Diameter ◽  
Median Diameter ◽  
The Mean

A pulsed wire discharge (PWD) apparatus for mass production of nanosized powders was developed. The apparatus had a wire feeder, and could prepare 1.5 g of Cu powder in 200 sec. The mean surface diameter of Cu powder was 86 nm. The particle size distribution of the powder prepared by 100 discharges was increased than that by one discharge. In addition, the median diameter of the powder after the 100 discharges was larger than that by one discharge. A part of the nanosized powders in production chamber of the apparatus would be grown by the deposition of plasma or vapor formed by the next discharge.

scholarly journals Optimized graded screen array configuration for particle size distribution of radon progeny in standard chamber

2019 ◽  
Vol 34 (3) ◽  
pp. 272-277
Author(s):  
Rui Chen ◽  
Shu-Min Zhou
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Collection Efficiency ◽  
Theoretical Calculations ◽  
Radon Progeny ◽  
Array Configuration ◽  
Comparison Research ◽  
Median Diameter ◽  
Array Measurement

Particle size distribution of radon progeny is one of the most important parameters and it needs to be measured accurately. Graded screen array measurement is the most frequently used method for analyzing the characteristics of radon progeny but it needs optimization due to its complex configuration. In this paper, collection efficiency of a single screen and the number of screen array were applied for optimization and simplification of the graded screen array configuration by a series of experimental measurements, theoretical calculations, and standard comparison research methods. When optimized in this way, an experiment was designed for radon progeny particle size distribution in a customized radon chamber. The experiment results indicated that the activity median diameter in unattached mode was 0.81 nm and 287.32 nm in attached mode, which were similar to the results obtained by other researchers. The results prove that the method can satisfy the requirements of graded screen array measurement.

scholarly journals Particle size distribution of airborne particulate matter in Petropavlovsk-Kamchatsky and Yelizovo based on the results of several years of study

2021 ◽  
pp. 66-72
Author(s):  
A. S. Kholodov ◽  
K. Yu. Kirichenko ◽  
K. S. Golokhvast
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Airborne Particulate Matter ◽  
Kamchatka Peninsula ◽  
Airborne Particulate ◽  
High Concentration ◽  
Anthropogenic Aerosols ◽  
Snow Samples

Introduction. Kamchatka Krai is a region with low population density and poorly developed industry. However, in large cities the air quality is degraded due to economic activity. Aim. To study the concentration of airborne particulate matter (in particular, up to 1 µm and up to 10 µm) in Petropavlovsk-Kamchatsky and Yelizovo air and carry out a comparative analysis with the previously obtained results of environmental monitoring of atmospheric suspension.Materials and methods. Airborne particulate matter was studied in snow which was collected during snowfalls to avoid its secondary pollution by anthropogenic aerosols. The melted snow was analyzed on a Fritsch Analysette 22 NanoTech laser particle analyzer (Germany).Results. PM1 particles were found in five snow samples taken in Petropavlovsk-Kamchatsky. The quantity of PM₁₀ is low in all samples, and only in two of six sampled areas it reaches 12%. Compared to the results of previous studies, the concentration of PM1 is at the same level as in previous years, and the content of PM₁₀ has decreased. In samples from Yelizovo, the same trends are observed. Compared to 2018, when a high concentration of PM₁₀ particles was found in almost all samples, reaching 57.2%, there is a trend towards a decrease in the concentration of the potentially hazardous PM fraction.Conclusion. Updated data on the particle size distribution of airborne particulate matter in two cities of the Kamchatka Peninsula were obtained. In the snow samples collected in Petropavlovsk-Kamchatsky and Yelizovo, we found PM₁ and PM₁₀ particles hazardous to human health, although their concentration is generally lower than in previous years of the study. 

Effects of Particle Size Distribution on Corrosion Rate of Carbon Steel in Soil

2020 ◽  
Vol 69 (4) ◽  
pp. 102-106
Author(s):  
Shota Ohki ◽  
Shingo Mineta ◽  
Mamoru Mizunuma ◽  
Soichi Oka ◽  
Masayuki Tsuda
Keyword(s):  
Particle Size ◽  
Carbon Steel ◽  
Corrosion Rate ◽  
Particle Size Distribution ◽  
Size Distribution
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